After installing ServiceStack.OrmLite.SqlServer NuGet Packages, I started getting below error out of no clue.
Method 'RemoveExpiredEntries' in type 'ServiceStack.Caching.MemoryCacheClient' from assembly 'ServiceStack, Version=5.0.0.0, Culture=neutral, PublicKeyToken=02c12cbda47e6587' does not have an implementation.
This indicates you have different version of ServiceStack packages. You need to make sure that all packages have the same version, e.g. 5.9.0.
Or if you're using the pre-release MyGet packages (e.g ending 5.*.1) then you'll need to clear out your NuGet packages cache so you can download the latest version, e.g:
nuget locals all -clear